Device and method for management of aneurism, perforation and other vascular abnormalities

ABSTRACT

This application is directed to a device comprising a covering attached to the device. A process of making a device with a specific covering attached is also disclosed. The application further discloses a method for the treatment of perforations, fistulas, ruptures, dehiscence and aneurisms in luminal vessels and organs of a subject.

This application claims priority of U.S. Provisional Patent ApplicationNo. 61/344,183, filed Jun. 7, 2010. The entirety of the provisionalapplication is incorporated herein by reference.

FIELD

This application generally relates to devices and methods for thetreatment of wounds in luminal vessels and organs, and other vascularabnormalities. In particular, the invention relates to a device andmethods for the treatment of perforations, fistulas, ruptures,dehiscence, punctures, incisions, and aneurisms in luminal vessels andorgans of a subject.

BACKGROUND

Current means of treating perforations in luminal vessels and organs isthrough operative procedures, endoscopic suturing, vascular closuredevices, or with an implant used for perforation management. However,current implants are big and have bulky coverings, are difficult to use,are not widely accepted, and are, in many cases, only used as a means oflast resort.

Aneurisms occur when an artery balloons out due to increased bloodpressure or a weakening in a blood vessel. Aneurisms can occurthroughout the body. Brain aneurisms, also known as intracranial orcerebral aneurisms, are life-threatening, particularly if they rupture.Once an aneurysm forms, it will not disappear on its own. Medication mayhelp slow its growth, but is not a cure. Most aneurisms eventually needrepair.

For the treatment of berry or saccular aneurisms, one current therapy isendovascular coiling, wherein a catheter is inserted into the femoralartery in the groin, through the aorta, into the brain arteries, andfinally into the aneurysm itself. Once the catheter is in the aneurysm,platinum coils are pushed into the aneurysm sac and released to allowthe aneurysm to clot or to change the turbulent flow and stop growingthrough a release or diversion of pressure. In another current therapy,the aneurysm is surgically treated by performing a craniotomy, exposingthe aneurysm, and closing the base of the aneurysm with a clip.

For fusiform aneurisms, a current treatment strategy is to place graftsthat do not degrade. These grafts have a history of collecting thrombithat can break off and get pushed further downstream. Another currenttreatment strategy is the surgical option of performing a bypass whichis technically challenging and has many complications on its own.

SUMMARY

One aspect of the present invention relates to a device for aneurism andperforation management. The device comprises a rigid, stent like bodyand an electrospun fibrous covering that covers the stent like body forincreased stability during placement.

In one embodiment, the stent like body comprises a biodegradable orbioabsorbable material.

In another embodiment, the biodegradable or bioabsorbable materialcomprises magnesium, iron, a polymer or co-polymer material.

In another embodiment, the stent like body comprises a non-biodegradableor non-bioabsorbable material.

In a related embodiment, the non-biodegradable or non-bioabsorbablematerial comprises stainless steel, cobalt chromium, or other alloy or anon-degradable polymer.

In another embodiment, the fibrous covering comprises a biodegradable orbioabsorbable material.

In a related embodiment, the biodegradable or bioabsorbable materialcomprises a poly-(α-hydroxy acid) or poly-(L-lactic acid).

In another embodiment, the fibrous covering comprises anon-biodegradable or non-bioabsorbable material.

In another embodiment, the covering material is mixed with bariumsulphate or other illuminating material.

In another embodiment, the stent like body is coated with a layer ofbiodegradable material and wherein the fibrous covering covers the layerof biodegradable material.

In a related embodiment, the stent like body is coated with the layer ofbiodegradable material by dip-coating.

In another embodiment, the stent like body is treated or etched withchemical agents, laser or abrasives to allow more effective attachmentof the electrospun fibrous covering to the stent like body.

In another embodiment, the stent like body is expandable.

Another aspect of the present invention relates to a method of makingdevice for aneurism and perforation management. The method comprisesdipping a rigid, stent like body in a biodegradable coating material toform a coated stent like body; and electrospinning fibers of a coveringmaterial onto the coated stent like body.

In one embodiment, the coated stent like body is covered byelectrospinning in a way that the fibers cross one another interlockingand forming angles.

Another aspect of the present invention relates to a method foroccluding an opening in a luminal vessel. The method comprises placingat the opening a device comprising an expandable stent like body coatedwith a biodegradable material and an electrospun fibrous covering thatcovers the stent like body; and expanding the stent like body toimmobilize the device at the opening.

In one embodiment, the luminal vessel is an artery or a vein.

In another embodiment, the opening is an aneurysm, perforation, ruptureor fistula.

In a related embodiment, the aneurysm is a berry aneurysm or a fusiformaneurysm.

In another related embodiment, the aneurysm is a cerebral, cardiac,pulmonary or aortic aneurysm.

Another aspect of the present invention relates to a method for treatingcondition in a luminal vessel in a subject. The method comprisesintroducing into the subject a device comprising an expandable stentlike body that is coated with a biodegradable material and covered withan electrospun covering; positioning the device at a treatment site; andexpanding the expandable stent like body to immobilize the device at thetreatment site.

In one embodiment, the expandable stent like body comprises magnesium,iron or a polymer material.

In another embodiment, the condition is plaque in a blood vessel.

In another embodiment, the condition is an acute myocardial infarction.

In another embodiment, the condition is a hole or an opening in saidluminal vessel.

In another embodiment, the condition is a grafted vessel. The device isemplaced under the graft to support the graft during the healing processand prevent leakage at sutures.

In another embodiment, the device covering can be further coated with adrug coating that can be eluted to minimize hyperplastic response or toinduce closure of the aneuryism

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-D show exemplary stent devices composed of bioabsorbablematerials such as: (A) magnesium, (B) iron, (C) composite material, and(D) a bioabsorbable covering.

FIG. 2 shows an exemplary stent device composed of a non-biodegradablematerial.

FIG. 3 shows an exemplary stent device crimped onto a catheter afterdip-coating or electrospinning.

FIG. 4 shows an exemplary stent device in dipped form.

FIG. 5 shows a magnified view of the stent device of FIG. 4.

FIG. 6 shows a crimped stent device comprising a covering of fibersapplied with electrospinning.

FIG. 7 shows a stent device comprising a covering of fibers applied withelectrospinning in a crimped state.

FIG. 8 shows a magnified view of the stent device of FIG. 7.

FIG. 9 shows the small circular structure within a covering of fibersapplied with electrospinning.

FIG. 10 shows electrospun fiber attached to stent device struts thathave been previously covered with electrospun material.

FIG. 11 shows a magnified view of the stent device of FIG. 10.

FIG. 12 shows the electrospun fibers on a stent device that has beenexpanded.

FIG. 13A-B shows a magnified view of the expanded stent device of FIG.12.

FIG. 14 shows the fibers on an electrospun stent device.

FIG. 15 shows a magnified view of the fibers of FIG. 14.

FIG. 16 shows a coated strut segment of a stent device.

FIG. 17 shows an unexpanded stent device.

FIG. 18 shows an unexpanded stent device that has been coated.

FIG. 19 shows an unexpanded stent device that has been coated.

FIG. 20 shows a magnified view of the coated stent device of FIG. 19.

FIG. 21 shows an electrospun stent device.

FIG. 22 shows a magnified view of the mesh structure on an electrospunstent device.

FIG. 23 shows a magnified view of the mesh structure on an electrospunstent device.

FIG. 24 shows a magnified view of the mesh structure on an electrospunstent device.

FIG. 25 shows a magnified view of the mesh structure on an electrospunstent device.

FIG. 26 shows a linear coating in a unidirectional form on a crimpedstent device.

FIG. 27 shows partial expansion of a stent device having a linearcoating in a unidirectional form.

FIG. 28 shows further expansion of a stent device having a linearcoating in a unidirectional form.

DETAILED DESCRIPTION

The following detailed description is presented to enable any personskilled in the art to make and use the invention. For purposes ofexplanation, specific nomenclature is set forth to provide a thoroughunderstanding of the present invention. However, it will be apparent toone skilled in the art that these specific details are not required topractice the invention.

One aspect of the present invention relates to a device for aneurism andperforation management. The device comprises a stent like body and acovering that covers the stent like body for increased stability duringplacement. In other embodiments, the device may further comprise othersupporting structure used for the implant. The device can be used totreat abnormal openings, such as perforations, fistulas, dehiscents, andaneurisms, in luminal vessels and organs. The device can be implantedinto the neurovascular, peripheral vascular, coronary, cardiac, andrenal systems, among others. The device allows the occlusion of a leakor weakening in a vessel wall, whereby the device reestablishes a normalpassage long enough for the lumen to heal.

The shape and the size of the stent like body may vary depending on theapplication of the device. The stent like body can be a stent or anexpandable stent. It is well known in the art that a stent is a deviceused to support a bodily orifice, cavity, vessel, and the like toreinforce collapsing, dissected, partially occluded, weakened, diseasedor abnormally dilated or small segments of a vessel wall. The stent likebody may be in any suitable form, including, but not limited to,scaffolding, a tube, a slotted tube or a wire form. The stent like bodymay be rigid, resilient, flexible, and collapsible with memory. In oneembodiment, the stent like body comprises a biodegradable orbioabsorbable material.

The material covering the stent like body will biodegrade and the stentlike body will remain if it is made from a non-biodegradable,non-bioabsorbable material. In certain embodiments, the stent like bodyis also made from a biodegradable or bioabsorbable material, and willdegrade after the degradation of the biodegradable covering. In otherembodiments, the stent like body is made from a biodegradable orbioabsorbable material, and is partially covered with the biodegradablecovering so that it will degrade with the biodegradable covering at thesame time but at a slower rate.

In one embodiment, the covering is an electrospun fibrous coveringcomprising a biodegradable material. In another embodiment, the coveringis attached to the stent like body by dip-coating process. In anotherembodiment, the stent like body is first coated with a biodegradablelayer by dip-coating process and then covered with an electrospunfibrous biodegradable covering.

In one embodiment, the covering covers the entire stent like body. Inanother embodiment, the covering covers a portion of the stent likebody. In another embodiment, the covering covers a majority of the stentlike body but leaves open an end portion of the stent like body. Inanother embodiment, the covering covers a majority of the stent likebody but leaves open a middle section of the stent like body.

The device is designed to occlude the abnormal opening long enough forit to heal or, in the case of an aneurysm, for it to occlude theaneurysm, be it a berry or fusiform aneurysm. Without wishing to bebound by theory, it is believed that the coating and/or the coveringallows the device to support the vessel wall or luminal wall over agreater surface area, thereby reducing the risk of a hyperplasticresponse. The covering may contain, or is further coated with, an agentthat reduces hyperplastic response.

As used herein, the term “biodegradable material” or “bioresorbablematerial” refers to a material that can be broken down by eitherchemical or physical process, upon interaction with the physiologicalenvironment at the implantation site, and erodes or dissolves within aperiod of time, typically within days, weeks or months. A biodegradableor bioresorbable material serves a temporary function in the body, suchas supporting a lumen or drug delivery, and is then degraded or brokeninto components that are metabolizable or excretable.

In some embodiments, the stent like body of the device is first coatedwith a biodegradable material through a dip-coating process and thencovered with the covering by electrospinning. The coating allows thecovering to adhere more effectively to the stent like body of thedevice. The coating may contain the same material as the biodegradablematerial of the covering, or another biodegradable material around thestent struts to promote adherence of the electrospun covering.

In particular embodiments, the stent like body is treated or etched withchemical agents, laser and/or abrasives to allow the electrospuncovering to adhere more effectively to the stent like body or othersupporting structure used for the implant. In such embodiments, thestent like body itself or the other supporting structure used for theimplant may or may not be coated with a biodegradable material prior toelectrospinning.

The stent like body can be made of a biodegradable or bioabsorbablematerial including, but not limited to, bioabsorbable metals or alloysand biodegradable polymer materials.

Examples of bioabsorbable metals and alloys include, but are not limitedto, lithium, sodium, magnesium, aluminum, potassium, calcium, cerium,scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel,copper, zinc, gallium, silicon, yttrium, zirconium, niobium, molybdenum,technetium, ruthenium, rhodium, palladium, silver, indium, tin,lanthanum, cerium, praseodymium, neodymium, promethium, samarium,europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium,ytterbium, lutetium, tantalum, tungsten, rhenium, platinum, gold, leadand alloys thereof.

In certain embodiments, the stent like body is made from an alloycomprising a combination of material that will decompose in the bodycomparatively rapidly, typically within a period of several months, andform harmless constituents. To obtain uniform corrosion, the alloy maycomprise a component, such as magnesium, titanium, zirconium, niobium,tantalum, zinc or silicon, which covers itself with a protective oxidecoat. A second component, such as lithium sodium, potassium, calcium,iron or manganese, which possesses sufficient solubility in blood orinterstitial fluid, is added to the alloy achieve uniform dissolution ofthe oxide coat. The corrosion rate can be regulated through the ratio ofthe two components.

Preferably, the alloy is to be composed so that the corrosion productsare soluble salts, such as sodium, potassium, calcium, iron or zincsalts, or that non-soluble corrosion products, such as titanium,tantalum or niobium oxide originate as colloidal particles. Thecorrosion rate is adjusted by way of the composition so that gases, suchas hydrogen which evolves during the corrosion of lithium, sodium,potassium, magnesium, calcium or zinc, dissolve physically, not formingany macroscopic gas bubbles.

Alternatively, the stent like body can be made of a non-biodegradableand non-bioabsorbable material including, but not limited to, stainlesssteel, titanium, chromium cobalt or a non-degradable polymer. The stentlike body can also be made of any suitable pharmaceutically acceptablealloy comprising, but not limited to, iron, magnesium, manganese,titanium, carbon, chromium, cobalt, molybdenum, nickel, aluminum,vanadium, zirconium, niobium, and/or tantalum. In some embodiments, thestent like body can also be made from a ceramic.

The covering of the device can be made of a biodegradable orbioabsorbable material such as, but not limited to, a poly-(α-hydroxyacid), preferably poly-(L-lactic acid). In a further embodiment, thecovering material can be mixed with barium sulphate or otherilluminating material to insure proper placement and visibility duringthe deployment using fluoroscopy, x-ray, or other imaging modalities.

In a particular embodiment, the biodegradable or bioabsorbable materialfor the covering of the device is formulated to begin to degrade in noless than 15 days after the device is emplaced in the subject. Inanother embodiment, the biodegradable or bioabsorbable material for thecovering of the device is formulated to begin to degrade in no less than30 days after the device is emplaced in the subject. In a furtherembodiment, the biodegradable or bioabsorbable material for the coveringof the device is formulated to begin to degrade in no less than 45 daysafter the device is emplaced in the subject. In still anotherembodiment, the biodegradable or bioabsorbable material for the coveringof the device is formulated to begin to degrade in no less than 60 daysafter the device is emplaced in the subject. In yet another embodiment,the biodegradable or bioabsorbable material for the covering of thedevice is formulated to begin to degrade in no less than 90 days afterthe device is emplaced in the subject.

In a certain embodiment, the biodegradable or bioabsorbable material forthe covering of the device is formulated to fully degrade within 90 daysafter the device is emplaced in the subject. In a further embodiment,the biodegradable or bioabsorbable material for the covering of thedevice is formulated to fully degrade within 120 days after the deviceis emplaced in the subject. In another embodiment, the biodegradable orbioabsorbable material for the covering of the device is formulated tofully degrade within 150 days after the device is emplaced in thesubject. In still another embodiment, the biodegradable or bioabsorbablematerial for the covering of the device is formulated to fully degradewithin 180 days after the device is emplaced in the subject. In yetanother embodiment, the biodegradable or bioabsorbable material for thecovering of the device is formulated to fully degrade within one yearafter the device is emplaced in the subject.

In one embodiment, the covering of the device comprises a copolymer madefrom 34% lactide, 35% caprolactone, 14% trimethylene carbonate, and 17%glycolide. The copolymer may be deposited on the stent like body byelectrospinning or by film coating. The copolymer coating would providestrength retention for 30-60 days and mass absorption in 9-12 months.

Initial coating of the strut segments of the stent like body has thebenefit and importance of insuring the coating thickness is much thickerat an area close to the struts, becoming thinner moving away from strutsto the center of a cell, allowing degradation to occur in the middle ofthe covering in the cell structure of the stent as well as allowing forcontrolled opening and crimping of the device during manufacturing anddeployment in the target lesions. This particular embodiment allows thecovering of the device to gradually degrade from the center of the celltowards the struts, and allows the device covering to maintain increasedapplied force to keep the covering in place against the luminal wallduring the degradation period.

In one embodiment, the stent like body itself is made from abiodegradable material so that it will be degraded after the degradationof the covering. In another embodiment, the stent like body itself ismade from a biodegradable material and is partially covered with thecovering so that the stent like body will start degradation at the sametime with the covering but at a slower rate. Electrospinning orientationis further enhanced through the adherence to the covered strut giving itgreater elasticity and the ability to orient to insure the maximum rangeof opening and closing of the device without tearing the covering. Thistechnique of applying the coverings allows the manufacture of a devicewith a very low profile of the covering material to cover the supportdevice and insure ease of delivery. Further, the elastic coverings ofthe present invention allow an expandable stent like body, whether it isballoon expandable or self expanding, to open to its nominal diameter.This is not possible based on the existing art. In one embodiment, thestruts of the stent like body are encased in the covering material in acircular form to provide the adherence.

Examples of biodegradable polymers include, but are not limited to,polydioxanone, polycaprolactone, polygluconate, poly(lactic acid)polyethylene oxide copolymer, modified cellulose, polyhydroxybutyrate,polyamino acids, polyphosphate ester, polyvalerolactone,poly-ε-decalactone, polylactonic acid, polyglycolic acid, polylactides,polyglycolides, copolymers of the polylactides and polyglycolides,poly-ε-caprolactone, polyhydroxybutyric acid, polyhydroxybutyrates,polyhydroxyvalerates, polyhydroxybutyrate-co-valerate,poly(1,4-dioxane-2,3-one), poly(1,3-dioxane-2-one), poly-para-dioxanone,polyanhydrides, polymaleic acid anhydrides, polyhydroxy methacrylates,fibrin, polycyanoacrylate, polycaprolactone dimethylacrylates,poly-β-maleic acid, polycaprolactone butyl acrylates, multiblockpolymers from oligocaprolactonediols and oligodioxanonediols, polyetherester multiblock polymers from PEG and poly(butylene terephthalates),polypivotolactones, polyglycolic acid trimethyl carbonates,polycaprolactone glycolides, poly(γ-ethyl glutamate),poly(DTH-iminocarbonate), poly(DTE-co-DT-carbonate), poly(bisphenolA-iminocarbonate), polyorthoesters, polyglycolic acid trimethylcarbonate, polytrimethyl carbonates, polyiminocarbonates,poly(N-vinyl)-pyrrolidone, polyvinyl alcohols, polyester amides,glycolized polyesters, polyphosphoesters, polyphosphazenes,poly[p-carboxyphenoxy)propane], polyhydroxy pentanoic acid,polyanhydrides, polyethylene oxide propylene oxide, soft polyurethanes,polyurethanes having amino acid residues in the backbone,polyetheresters such as polyethylene oxide, polyalkene oxalates,polyorthoesters as well as copolymers thereof, lipids, carrageenans,fibrinogen, starch, collagen, protein based polymers, polyamino acids,synthetic polyamino acids, zein, polyhydroxyalkanoates, pectic acid,actinic acid, carboxymethyl sulfate, albumin, hyaluronic acid, chitosanand derivatives thereof, heparan sulfates and derivates thereof,heparins, chondroitin sulfate, dextran, β-cyclodextrins, copolymers withPEG and polypropylene glycol, gum arabic, guar, gelatin, collagenN-hydroxysuccinimide, lipids, phospholipids, polyacrylic acid,polyacrylates, polymethyl methacrylate, polybutyl methacrylate,polyacrylamide, polyacrylonitriles, polyamides, polyetheramides,polyethylene amine, polyimides, polycarbonates, polycarbourethanes,polyvinyl ketones, polyvinyl halogenides, polyvinylidene halogenides,polyvinyl ethers, polyisobutylenes, polyvinyl aromatics, polyvinylesters, polyvinyl pyrrolidones, polyoxymethylenes, polytetramethyleneoxide, polyethylene, polypropylene, polytetrafluoroethylene,polyurethanes, polyether urethanes, silicone polyether urethanes,silicone polyurethanes, silicone polycarbonate urethanes, polyolefinelastomers, EPDM gums, fluorosilicones, carboxymethyl chitosanspolyaryletheretherketones, polyetheretherketones, polyethyleneterephthalate, polyvalerates, carboxymethylcellulose, cellulose, rayon,rayon triacetates, cellulose nitrates, cellulose acetates, hydroxyethylcellulose, cellulose butyrates, cellulose acetate butyrates, ethyl vinylacetate copolymers, polysulfones, epoxy resins, ABS resins, EPDM gums,silicones such as polysiloxanes, polydimethylsiloxanes, polyvinylhalogens and copolymers, cellulose ethers, cellulose triacetates,chitosans and copolymers and/or mixtures of the aforementioned polymers.

In a particular embodiment, the device comprises visibility or opacitytechnology allowing visualization of the device using an imaging meansor imbedding the covering or strut coating with the same or variousdrugs or illuminating material. In another embodiment, the coveringallows the stent to freely float or to move in a controlled manner underthe coating and covering, with the level of restriction depending on thethickness of said covering or coating. In another embodiment, thecovering or coating has varying degrees of degradation. If the coveringwas formed by the electrospinning, the filaments would be intertwinedand set with such angles to allow the stent to be crimped and opened asrequired in normal applications and the degradation could be controlledby the density of the material established by the number of filamentcrossings and the angles to absorb the load and stresses of opening andclosing and anatomical compressions. Furthermore, the material of thesupport, coating and covering of the device allow normal body fluids toflow unobstructed. In yet another embodiment, the device is covered in asingle layer, double layer, triple layer or multiple layers depending onthe need. The covering can be on the outside of the stent like body, onthe inside of the stent like body, or encapsulating the of the stentlike body.

In another embodiment, the device comprises a therapeutically effectiveamount of a therapeutic agent or agents. In particular embodiments, thedevice comprises at least one therapeutic agent. In other embodiments,the device comprises one therapeutic agent or more than one therapeuticagent. In still other embodiments, the device comprises two, at leasttwo, three, four, or five therapeutic agents. In a particularembodiment, a therapeutic agent comprised on the device is an analgesicor anesthetic agent. In another particular embodiment, a therapeuticagent comprised on the device is an antibiotic, antimicrobial,antiviral, or antibacterial agent. In another embodiment, a therapeuticagent comprised on the device is a thrombotic or coagulant agent. Inanother embodiment, a therapeutic agent comprised on the device is ananti-thrombotic or anticoagulant agent.

In certain embodiments, the therapeutic agent is comprised in apharmaceutical composition formulated for sustained-release.Sustained-release, also known as sustained-action, extended-release,time-release or timed-release, controlled-release, modified release, orcontinuous-release, employs a pharmaceutically acceptable agent thatdissolves slowly and releases the therapeutic agent over time. Asustained-release formulation allows the topical release of steadylevels of the therapeutic agent directly at the site where it would betherapeutically effective.

In one embodiment, the pharmaceutical composition is formulated forsustained release by embedding the active ingredient in a matrix ofinsoluble substance(s) such as acrylics or chitin. A sustained releaseform is designed to release the therapeutic agent at a predeterminedrate by maintaining a constant drug level for a specific period of time.This can be achieved through a variety of formulations, including, butnot limited to liposomes and drug-polymer conjugates, such as hydrogels.

In another embodiment, the therapeutic agent is comprised in apharmaceutical composition formulated for delayed-release, such that thetherapeutic agent is not immediately released upon administration. Anadvantage of a delayed-release formulation is that the therapeutic agentis not released from the device until the device has been emplaced inthe desired location. In some embodiments, the therapeutic agent isfirst coated onto the device and is then coated over with apharmaceutical composition formulated for delayed-release.

In a particular embodiment, the therapeutic agent is delivered in avehicle that is both delayed release and sustained release.

In another embodiment, a therapeutic agent comprised on the device isapplied to the exterior surface of the device. A therapeutic agent maybe applied to the exterior of the cover or may be mixed or imbedded intothe covering material. In some embodiments, the device may contain anadditional coating on its exterior that delays the release of thetherapeutic agent or modulates the release of the therapeutic agent overtime. In one embodiment, the covering of the device is further coatedwith a drug coating that can be eluted to minimize hyperplastic responseor to induce closure of the aneurysm.

In another embodiment, a therapeutic agent comprised on the device isapplied to the interior surface of the device. In further embodiments,therapeutic agents are applied to both the interior and to the exteriorsurfaces of the device. Therapeutic agents applied to the interior andexterior surfaces of the device may be the same or different. As anon-limiting example, a coagulant agent may be applied to the exteriorsurface of the device to facilitate the healing of a perforation, whilean anti-coagulant may be applied to the interior of the device toprevent restriction of the flow of bodily fluids and cells through thedevice.

Various biodegradable or bioabsorbable implants can be used in thecoronary, peripheral vascular, or non-vascular space that could becovered with the electro spinning process or dip-coated process to beused to occlude various defects or leaks. Exemplary materials include,but are not limited to, magnesium (FIG. 1A), iron (FIG. 1B), or polymermaterials (FIG. 1C). Coverings of the device (FIG. 1D) can also be madeof biodegradable or bioabsorbable materials.

The device can also be made from a material that is not biodegradableand that is a more traditional and commonly used material such as, butnot limited to, stainless steel, titanium or cobalt chromium (FIG. 2).The device can also be made of any suitable pharmaceutically acceptablealloy comprising, but not limited to, iron, titanium, carbon, chromium,cobalt, molybdenum, nickel, aluminum, vanadium, zirconium, niobium,and/or tantalum. The stent like body of the device can also be made froma ceramic. This stent like body would be coated or spun in the tubediameter it was cut from, or some other diameter from about 50% less thetube diameter to about 100% of its maximum expanded diameter which is anembodiment of this process to assist with the expansion of the stent.

The device can be crimped to its nominal diameter on a catheter (FIG. 3)after it is covered from an electrospinning or dip-coated process.

Use of the Device

A further aspect of the present invention is a method of treating ananeurysm or occluding an opening in a luminal vessel in a mammal usingthe device of the present invention.

In another embodiment, the opening in the luminal vessel has beensutured, stapled, cauterized or glued and the device is used to supportthe luminal wall during the healing process and prevent leakage.

The aneurysm may be a cerebral aneurysm, an aortic aneurysm or aperipheral aneurysm. The form of the aneurysm may be fusiform, saccularor berry.

The device may also be used in the treatment of a perforation, fistula,or dehiscent in a vessel.

A further embodiment for use of the present invention is carotidstenting, wherein placement of the device prevents a plaque frombreaking off during stent placement and to insure the plaque is trappedbehind the implant until the covering dissolves.

Another embodiment is in the treatment of an acute myocardialinfarction, wherein placement of the device traps a thrombus or othersuch material or plaque against the luminal wall to prevent the thrombusfrom being pushed down stream.

A further embodiment for use of the present invention is in associationwith graft placement, wherein the device is emplaced under a graft tosupport it during the healing process and prevent leakage at thesutures.

In each of these methods, the method comprises the steps of (a)introducing into the subject a device comprising (i) a stent like bodycoated with a biodegradable material, and (ii) an electrospun fibrousbiodegradable covering that covers said stent like body, (b) positioningthe device adjacent to the area in need of treatment, and (c) expandingthe device to allow it stays at the treatment site.

After implantation, the material covering the stent like body willbiodegrade and the stent like body will remain if it is made from anon-biodegradable, non-bioabsorbable material. In certain embodiments,the stent like body is also made from a biodegradable or bioabsorbablematerial, and will degrade after the degradation of the biodegradablecovering. In other embodiments, the stent like body is made from abiodegradable or bioabsorbable material, and is partially covered withthe biodegradable covering so that it will degrade with thebiodegradable covering at the same time but at a slower rate.

Dip-Coating

Stent in dip-coated form (FIG. 4) has an increased covering thicknessaround the strut segments to allow for expansion, having ripples 1 inthe material that will allow it to expand beyond the current state. Thedevice with a higher thickness or density of coating starting with theindividual struts and then dip-coated again after to insure that thedevice covering will degrade from the middle of the cell 2 to thestruts. Higher magnification (FIG. 5) shows that the covering is thickeraround the arch of the stent 3 and tapers off as you move away from thestruts. The covering is much thinner in the middle of the cell 4 thanclose to the struts, allowing the device to biodegrade from the middleof the cell to the strut segments versus at the attachment points to thestruts.

Electrospinning

The process of electrospinning can be carried out by any method known inthe art. The method used in the present invention is not to be limitedto a single method of electrospinning. Exemplary, non-limiting,processes for electrospinning are described, for example, by Yuan, X etal. (Yuan, X et al. Characterization of Poly-(L-Lactic Acid) FibersProduced by Melt Spinning. J. Appl. Polym, Sci. 2001, 81:251-260.) andin ZEUS Technical Newsletter, Electrospinning—Fibers at the Nano-scale.2009 (Zeus Industrial Products, Inc., Orangeburg, S.C.).

In the coating of the device by electrospinning, the device is coveredin a way that the fibers cross one another interlocking and formingangles. In one embodiment, the fibers intersect one another at angleswith angles from about 1, 5, 10, 15, 20, 25, 30, 35, 40 or 45 degrees toabout 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95 degrees. In anotherembodiment, the fibers intersect one another at angles with angles fromabout 1 degree to about 95 degrees. In a further embodiment, the fibersintersect one another at angles with angles from about 5 degrees toabout 95 degrees. In another embodiment, the fibers intersect oneanother at angles with angles from about 10 degrees to about 90 degrees.

The fibers are overlapped to allow for the stresses during crimping,loading, and expansion to be born by all the materials filaments withthe stress loads being on the various filaments and their respectiveangles which allows the distribution of the stresses and the loads inall directions versus a uniform direction which is required for theopening and closing of a cylindrical tube of varying lengths. In oneembodiment, the fibers are overlapped a minimum of about 1 time and amaximum of about 1000 times. In a preferred embodiment, the fibers areoverlapped a minimum of about 1 time and a maximum of about 500 times.In another preferred embodiment, the fibers are overlapped a minimum ofabout 2 times and a maximum of about 500 times. Yet in another preferredembodiment, the fibers are overlapped a minimum of about 2 times and amaximum of about 400 times. In still another preferred embodiment, thefibers are overlapped a minimum of about 2 times and a maximum of about300 times. In a more preferred embodiment, the fibers are overlapped aminimum of about 2 times and a maximum of about 200 times. In a mostpreferred embodiment, the fibers are overlapped a minimum of 2 times anda maximum of 200 times.

FIG. 6 shows a crimped stent that has an electrospun covering. Amagnified view of the same stent (FIG. 7) in its crimped state shows theelectrospun fibers with mesh like cross section fibers 5. An angle 6 ofthe electrospun material allows the device to be opened to its fullexpansion through the use of the preformed angle of the electrospunmaterial. Shapes which form in the mesh, such as a triangle 7, circles,rectangles, or ovals allow the device to expand to its optimal diameter.This design shows that through the use of various geometrical shapes thedevice can expand without putting fibers under strains that cause themto break.

An electrospun stent may have a porous structure (FIG. 8) in a honeycombpattern or circle chain links that allow the covering to expand duringthe opening process of the device. This porous structure can compriselarge interlocking circles 8, a deep honeycomb structure 9, and smallcircular structures 10 that allow for expansion and ease of drug loadingas well as visibility material.

In a device having a covering formed by an electrospinning apparatushaving a conical circular opening that release the polymers (FIG. 9),variation in the strand fibers and the hole sizes 11 are regulated andoriented by changes in heat, viscosity of the material and molecularchain lengths. Modifying the opening of the dispersion tube thatreleases the material to be electrospun can modify the covering fiberthickness.

One can further modify the flow and alignment of the polymer fibers bychanging the opening shape from a circle to one in the shape of an oval,cross, diamond, star, octagon, other polygons or other such shapes.Additionally, the dispersing tube can have a tapered inner surface ofvarying shapes that can also modify the process of alignment orapplication. Additionally, because the material and the receiving devicehave different charges, you can further control the fiber application byreversing the direction of the application device versus moving thecoated device to modify the fiber orientation. By moving the applicatorcone versus the device in the opposite or in the direction of thedesired laying down of the fibers one can better control the fiberangles, shapes, and thickness to achieve the desired or optimal results.The shape of the holes 12, 13 can also be varied by the applicationprocedure.

Electrospun fiber can be attached to struts that have been previouslycovered with electrospun material (FIG. 10) to insure that the strutshave a thicker amount of material than the center of the cell and thatthe material has increase sticking and elastic characteristics. In thiscase, the denser more fibrous adherence is aligned on the struts 14,while the center of the cells 15 have less of the covering but stillhave the porous and cross sectional aspect of the fibers.

A magnified view of the optimal fiber alignment (FIG. 11) shows thestrut adherence 16 and the center of the cell structure 17 and optimalorientation of circular and fibrous longitudinal fibers as well asangulations that form the optimal covering for the stent.

The configuration allows the fibers to maintain their integrity when thestent is expanded (FIG. 12), where the fibers maintain their optimalorientation in the expanded form, as seen in the center of the cells 18,19. Further magnification of the expanded stent (FIG. 13) shows theoptimal configuration of the fibers adhered to the strut of the stent20. Yet further magnification shows that the structural fibers 21 areoptimal for expansion and red blood cells or drug application.

Magnification of fibers on an expanded stent (FIG. 14) show how thestretch coming off the struts and the various optimal shapes formedduring the electrospinning process to allow for expansion. The shapesmay include: a “Y” or “V” angulated connector 22 for optimal expansion,multiple circular connect rings of varying sizes 23, or a large basecircle 24 that may be integrated with smaller base circles 25. Themaximum density of the electrospun covering at center of the struts 26tapers to a lower density away from the center of the struts 27 and to alower density at the edges of the struts 28. A further magnified view ofthe stent covering (FIG. 15) shows the detailed view of the angulatedmesh 29 allowing for optimal expansion.

FIG. 16 shows a magnified view of a coated strut segment, while FIG. 17shows an unexpanded stent. Another view of a covered stent (FIG. 18)shows increased thickness close to stent strut 30, the elasticity of thepolymer fibers connected to the strut segments 31 and the elongatedconnectivity 32.

Further magnification of an electrospun coated stent (FIG. 19) shows thethickness around strut segments 33, 34.

Close up of the stent with angles of 5% to 95% and circle combinations(FIG. 20) shows connectivity to covered stent fiber and directionalcovering 35 and the circle and fiber orientation and combination 36.

A view of an electrospun stent (FIG. 21) shows angles in the covering ata macro level 37 and covered filaments 38.

A microscopic view of the mesh (FIG. 22) and the cross orientation thatallows for expansion of the mesh shows a view of an expanded micro cell39. A lower magnification (FIG. 23) of the same angle 40 is seen in anexpanded view of the mesh. FIG. 24 shows an electrospun coating with adifferent orientation and filament thickness 41.

Electrospinning allows the formation of various fibers and angles withdifferent filament thickness (FIG. 25). Additionally, variation ofcrystalinity by spinning the material on the device when the device isat a variant temperature of up to 38° C. above or below room temperaturewill have an impact on the formation of the patterns, adherence to thedevice, and filament roughness or smoothness. Based on a temperaturechange in the spinning process and a combination of a change in thedevice, the orientation patterns of the spun filaments as well as theelasticity of the filaments can be modified. For example, if the deviceis cold and the spun material is hot, this will substantially change theoutcome versus if the device and the material are at the sametemperature.

Variations in processing have an impact on changing the filament surfacecharacteristics 42. Changing the surface quality of the filamentsaffects their ability to expand or to have more friction, depending onthe actual surface quality of the filaments, which has a direct impacton the opening behavior of the device; smoother surface, easier opening,and less tearing of the filaments. Greater roughness of the fiberstranslates to a greater surface area coefficient of friction and thepotential to increase risk of tearing or when there is a filamentdisruption for the others to maintain their integrity 43.

Electrospinning provides an advantage over linear coating of a stent ina unidirectional form (FIG. 26), because the linear coating does notprovide a mesh which allows elasticity of the coating as the device isexpanded. Accordingly, as a linear coated device is expanded, this lackof elasticity results in the destruction of the fibers (FIG. 27) andfailure in the expanded stent (FIG. 28) to provide a surface capable ofoccluding an opening in a luminal vessel.

The above description is for the purpose of teaching the person ofordinary skill in the art how to practice the present invention, and itis not intended to detail all those obvious modifications and variationsof it which will become apparent to the skilled worker upon reading thedescription. It is intended, however, that all such obviousmodifications and variations be included within the scope of the presentinvention, which is defined by the following claims. The claims areintended to cover the components and steps in any sequence which iseffective to meet the objectives there intended, unless the contextspecifically indicates the contrary.

What is claimed is:
 1. A device for aneurism and perforation management,comprising: a rigid stent body comprising a plurality of cells formed bya set of struts, wherein each cell has a center, and wherein the stentbody is coated with a layer of biodegradable material comprising abiodegradable polymer, wherein at an area close to said stent body'sstruts the layer of biodegradable material is coated thicker relative tocoating moving away from the stent body's struts towards the centers ofeach cell; and an electrospun fibrous covering comprising abiodegradable material, wherein the electrospun fibrous covering coverssaid layer of biodegradable material and said stent body for increasedstability during placement; wherein said layer of biodegradable materialpromotes adherence of the electrospun fibrous covering, wherein fiberswithin said electrospun fibrous covering interlock and overlap formingshapes comprising angles and rings of varying sizes, and wherein thelayer of biodegradable material contains the same material as thebiodegradable material of the electrospun fibrous covering, and furtherwherein the electrospun fibrous covering covers at least a portion ofthe stent body.
 2. The device of claim 1, wherein said stent bodycomprises a biodegradable or bioabsorbable material.
 3. The device ofclaim 2, wherein said biodegradable or bioabsorbable material comprisesmagnesium, iron or a polymer or co-polymer material.
 4. The device ofclaim 2, wherein said stent body is partially covered with theelectrospun fibrous covering, such that the stent body will startdegradation at the same time as the electrospun fibrous covering, but ata slower rate.
 5. The device of claim 1, wherein said stent bodycomprises a non-biodegradable or non-bioabsorbable material.
 6. Thedevice of claim 5, wherein the non-biodegradable or non-bioabsorbablematerial comprises stainless steel, cobalt chromium, or a non-degradablepolymer.
 7. The device of claim 1, wherein the electrospun fibrouscovering comprises a bioabsorbable material.
 8. The device of claim 7,wherein the bioabsorbable material in the electrospun fibrous coveringcomprises a poly-(α-hydroxy acid) or poly-(L-lactic acid).
 9. The deviceof claim 1, wherein the electrospun fibrous covering comprising thebiodegradable material is mixed with barium sulphate or otherilluminating material.
 10. The device of claim 1, wherein said stentbody is coated with said layer of biodegradable material by dip-coating.11. The device of claim 1, wherein said stent body is treated or etchedwith chemical agents, laser or abrasives to allow more effectiveattachment of said electrospun fibrous covering to said stent body. 12.The device of claim 1, wherein said stent body is expandable.
 13. Thedevice of claim 1, wherein said biodegradable material comprised in theelectrospun fibrous covering is formulated to fully degrade within oneyear after the device is emplaced in a subject.
 14. The device of claim1, wherein said stent body is made from a metal alloy comprising a firstcomponent selected from the group consisting of magnesium, titanium,zirconium, niobium, tantalum, zinc and silicon, wherein said firstcomponent is covered with a protective oxide coat; and a secondcomponent selected from the group consisting of lithium, sodium,potassium, calcium, iron or manganese.
 15. The device of claim 1,wherein the biodegradable polymer in the layer of biodegradable materialis poly (lactic acid) or poly-(α-hydroxy acid).